My first son was conceived with Clomid and some other meds to regulate my hormones. After he was born, we tried again and Clomid didn't work at all for me. I was on Pergonal and Metrodin (this was in the early 90s - I think Metformin might be the same thing with just a different name). That didn't work and I tried other treatments such as a GNRH pump and In Vitro. We went back to just the injectables and I got pregnant with twins. After my twins were born, we tried IVF and injectables again and nothing worked and we decided our family was complete. A few years later, we found out I was pregnant again.
Everyone is so different, though. It's hard to say what will work for you. It was very frustrating to go through all of the treatments. In my case, the injectables didn't work in low doses, then worked too well in high doses and I would get hyperstimulation syndrome. It was very tricky for my doctors to treat me.
Good luck!!
Erica